This project is directed at characterizing the time of appearance of specific neurotransmitter properties during development of the vertebrate retina. It will utilize biochemical, autoradiographic, morphological and physiological techniques to follow the time of appearance of the high affinity uptake for specific neurotransmitters, the time when neurotransmitters are first synthesized during development, time when release of neurotransmitters can first be evoked and the time of post-synaptic receptor appearance. Using dissociated neuroepithelial cells derived from retinal rudiments from the embryo maintained in tissue culture, we will determine the requirements for cell-to-cell contacts during retinal differentiation for the appearance of specific neurotransmitter properties. The project will also involve an analysis of the factors which regulate membrane assembly in photoreceptors. It will systematically evaluate the involvement of cyclic nucleotide metabolism, phosphorylation reactions, and calcium fluxes in establishing the burst of membrane assembly at the base of rod outer segments which follows the onset of the light cycle. The project will also evaulate the involvement of environmental lighting in setting the rates of metabolism of RNA and protein synthesis within the retina. A basic understanding of the regulation of retinal development, renewal processes and rates of retinal metabolism will provide important new information to understanding the control of these processes in retinal health and disease.